A toilet generally includes a bowl and a toilet tank. As shown in FIG. 9, the conventional toilet tank (90) typically includes a discharge tube (91), an overflow tube (92) and a valve cap (93) pivotally connected to the overflow tube (91) to selectively close the discharge tube (91). The operation of the valve cap (93) is controlled by a string (96) connected to an arm (95) that is rotatable by a handle (94).
As illustrated, when the handle (94) is rotated, the string (96) is lifted by the arm (95) and the valve cap (93) is pivoted from a closed position to an open position to discharge water from the toilet tank (90). The valve cap (93) returns to the closed position once the discharge is completed, and the toilet tank (90) is ready to be refilled.
A disadvantage of the conventional toilet tank (90) is that water therein is totally discharged once the handle (94) is activated, regardless of what kind of waste is in the bowl. In other words, excessive amounts of water are wasted.